1. Field of the Invention
The invention relates to a coaxial conductor, more particularly to a coaxial conductor which includes a coaxial cable and a BNC coax connector.
2. Description of the Related Art
Referring to FIG. 1, a conventional coaxial conductor is shown to comprise a BNC coax connector (10), a coaxial cable (20) and a sleeve (30). The coax connector (10) includes a stationary seat (11), a tubular inner conductive portion (12) and a tubular outer conductive portion (13) which is insulated electrically from the inner conductive portion (12). Referring to FIG. 2, the coaxial cable (20) includes a center conductor (21), a braided outer conductor (22), a dielectric (23) which separates the center conductor (21) from the braided outer conductor (22) and an insulating jacket (24) which is provided around the braided outer conductor (22). The sleeve (30) covers the electrical connection between the coax connector (10) and the coaxial cable (20) and has a wide tubular part (31) at a front end and a narrow tubular part (32) at a rear end.
FIGS. 3, 4 and 5 illustrate the assembly of the conventional coaxial conductor shown in FIG. 1. One end of the insulating jacket (24) is stripped so as to expose a portion of the braided outer conductor (22). The exposed portion of the braided outer conductor (22) is then pulled over the insulating jacket (24) so as to expose a portion of the dielectric (23). One end of the dielectric (23) is stripped so as to expose a portion of the center conductor (21). During assembly, the stripped end of the coaxial cable (20) is extended through the sleeve (30) via the narrow tubular part (32), as shown in FIG. 3. The center conductor (21) is then extended into the inner conductive portion (12) of the coax connector (10) and is welded or riveted thereto. The wide tubular part (31) of the sleeve (30) is in tight frictional engagement with the outer conductive portion (13) of the coax connector (10). A crimping tool (not shown) is then used so as to crimp the narrow tubular part (32) of the sleeve (30) to the coaxial cable (20). The drawbacks of the conventional coaxial conductor shown in FIG. 1 are as follows:
1. Referring to FIG. 5, the cross-section at the crimped portion of the narrow tubular part (32) of the sleeve (30) deviates from a circle to an oval when the narrow tubular part (32) is crimped to the coaxial cable (20). Thus, only two opposite portions of the exposed portion of the braided outer conductor (22), which was pulled over the insulating jacket (24), are in tight contact with the sleeve (30). This results in an unstable engagement between the sleeve (30) and the coaxial cable (20).
2. Deformation of the dielectric (23) similarly occurs because the crimping force is applied on only two opposite portions thereof. This can affect the insulating characteristics of the dielectric (23), thereby affecting correspondingly the signal transmission characteristics of the coaxial cable (20).
3. The sleeve (30) contacts only two opposite portions of the exposed portion of the braided outer conductor (22), thereby resulting in a relatively small electrical contact area.
Referring to FIG. 6, it is also known in the art to crimp the sleeve (30) to the coaxial cable (20) in such a manner that the cross-section of the former is changed to a hexagonal structure. Such a structure, however, cannot sufficiently overcome the above mentioned drawbacks.